MedImmune Recalls 13 Lots of Intranasal H1N1 Vaccine

A second manufacturer is recalling novel influenza A (H1N1) vaccine because of potency issues.

AstraZeneca's MedImmune biologics unit said Dec. 22 that it is recalling 4.7 million doses (3-page PDF; About PDFs) of its live, attenuated intranasal H1N1 vaccine after nine lots failed stability testing. Four other lots that still met specifications during testing also were recalled as a precautionary measure.

The affected lots, which were distributed nationwide, are

Vaccine potency can diminish over time, which is why manufacturers perform routine stability tests until a lot reaches its expiration date. MedImmune said all of the affected lots passed safety, purity and potency tests prior to their release.

The manufacturer also said that vaccine potency was only slightly below specifications during follow-up tests. The vaccine in the affected lots is still expected to be effective in stimulating a protective response, and there is no need to readminister a dose to those who received vaccine from these lots, MedImmune said.

Reuters, quoting FDA officials, reported on Dec. 22 that only about 3,000 of the doses remain in warehouses, and the majority of the vaccine was administered in October and November while still at full potency.

MedImmune said it is notifying physicians and other providers who received doses from affected lots so they can return any unused vaccine.

The MedImmune vaccine recall was the second attributed to potency issues in two weeks. Sanofi Pasteur Inc. announced Dec. 15 that it was recalling about 800,000 doses of its novel influenza A (H1N1) vaccine after four lots of single-dose pediatric vaccine in 0.25 mL prefilled syringes failed stability testing.

As with the MedImmune recall, people who received vaccine from Sanofi's recalled lots are not recommended to receive an additional dose, according to the CDC.